09-271
To: J3
From: Robert Corbett
Subject: message about floating-point exceptions
Date: 2009 July 27
References: 09-007r2
1. Introduction
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Users hate it when programs issue warnings about floating-point
exceptions on termination.
2. Discussion
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Sun f77 used to issue a retrospective message about
floating-point exceptions on termination. The message was a
constant source of complaints from users. Sun f77 did not
issue a restrospective message if the only floating-point
exception that was signaling was the inexact exception.
Telling a user that his program signaled an inexact
exception is tantamount to telling telling him that his
Fortran program has done some floating-point arithmetic.
A former member of this committee was among the most vocal
critics of the retrospective message.
I know that the IEEE floating-point standard requires such a
message to be issued. Users do not care. The Fortran
standard does not conform to the IEEE standard in other ways,
such as not changing the values of floating-point constants
when the rounding mode changes.
3. Edits
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[187:13-16 8.4p2]
Delete the second sentence of paragraph 2. In the third
sentence, replace "same unit." with "unit identified by the
named constant ERROR_UNIT (13.8.2.8).
[187:16+ Note 8.27]
Delete the phrase "and signaling exceptions".